Process for the polymerization of butadiene in the presence of a catalyst system comprising an organo ni or co compound,a chloride of sn or ga and an organolithium compound



United States Patent 23,292/ 65 US. Cl. 260--94.3 11 Claims Int. Cl. C08d 1/14; B01j 11/84 ABSTRACT OF THE DISCLOSURE A process for the preparation of polybutadiene in which at least 80% of the monomer units are present in cis 1,4 addition structure, wherein butadiene is polymerized in the presence of a catalyst system obtained by bringing togetl1 er (A) a compound which is preferably soluble in an organic solvent selected from a group comprising nickel or cobalt carboxylic acid salts and organic complex compounds wherein the metal atom is other than zerovalent, (B) a compound selected from the group c0mprising the chlorides of gallium and tin, and (C) an organo-metallic compound of lithium selected from the group comprising lithium alkyls, lithium aryls and lithium aralkyls, the lithium component (C) only being contacted with the other components of the catalyst system whenin the presence of butadiene.

This invention relates to the polymerization of butadiene to a rubbery polymer of high cis 1,4 structure. 7

According to the present invention, polybutadiene, in which at least 80% of the monomer units are present in cis 1,4 addition structure, is prepared by polymerizing butadiene in the presence of a catalyst system obtained by bringing together (A) a nickel or cobalt compound not containing a halogen directly attached to the metal atom, (B) a tin or gallium chloride and (C) .a lithium'alkyl, the lithium component (C) onlybeing contacted. with the other components aryl or aralkyl, of the catalyst system when in the presence of butadiene. t

' The cis 1,4 content of the polybutadiene, at least 80%, is usually greater than 90%, 2.9% vinyl 1,2. The trans content of 'the polymer" varies with the cis content, the vinyl content remaining substantially constant. The molecular weight of the polybutadiene prepared using this catalyst system lies within the range 15,000-100,000.' H I All three components in this catalystcombina'tion are necessary to polymerize butadiene to polybutadiene'of high cis 1,4 structure and no two components, without the third, will work satisfactory.

It has been found that the molecular 'weight of the product and the rate of polymerization are affected by'the molar ratios of the catalyst components, AzB" and CzB. The ratio of component (A) to component (B should lie within the range 0.01-1.0z1, preferably within therange 0.05-0.25 :1 and the ratio of component (C) to component (B) should be within therange 0.5-2.5 :1, preferably within the range 0.8-1.5:1. v r

Preferably thenickel or cobalt compound is one which is soluble in organic solvents such as hexane or benzene. Examples of suitable nickel compounds include nickel acetylacetonate, nickel octoate, nickel di-isoprop'ylsalicylate, nickel naphthenate, nickel benzoate and nickel acetoacetate. Nickel di-isopropylsalicylate', described in our e.g., 95.2%"cis, 1.9% trans, o

ICC

pending British application No. 49,679/ 64, is a particularly suitable nickel compound. Suitable cobalt compounds include cobalt acetylacetonate, cobalt octoate and cobalt di-isopropylsalicylate. These compounds are nickel or CO balt carboxylic acid salts or organic complexes in which the metal atom is other than zerovalent.

Component (B) may be either tin tetrachloride or gallium trichloride. Examples of suitable lithium compounds for component (C) include n-butyl lithium, ethyl lithium, phenyl lithium, octyl lithium, sec-butyl lithium and isobutyl lithium.

The polymerization is preferably carried out in the presence-of a substantially dry hydrocarbon solvent such as hexane or benzene. However, traces of water, for example, within' the range 1-20 parts per million in the solvent, dependent upon catalyst concentration, may have advantageous elfects on the rate of polymerization and help to regulate the molecular weight of the product.

The temperature at which the polymerization is performed is usually within the range 0 C. to +100 C. but polymerization may be performed at higher and lower temperatures. The preferred temperature range is from 40 C. to 60 C. At the lower temperatures, 0-20" C., some polymer is formed, but yields are comparatively low. The temperature used also affects the molecular weight of the product. Thus at low temperatures polybutadiene is obtained having a higher molecular weight than that obtained at high temperatures.

It has been found that the mode of the addition of the catalyst components is important to obtain high rates of polymerization and preferably the lithium component (C) does not come into contact with either the tin or gallium chloride (B), or the nickel or cobalt compound (A) in the absence of butadiene. If the butadiene is designated component (D) then the following orders of addition are acceptable:

(A+B), D, C

, Of these, D, A, B, C is particularly preferred. I Orders of addition as follows are not desirable:

It has also been found advantageous to add the component'(C) in two portions. The first aliquot added to the butadiene plus solvent is completely deactivated by the impurities in the butadiene and solvent. The amount of component (C) added at this stage is preferably 75% of the theoretical catalyst demand for purification.

An improvement in the work up of the catalyst system has also been found when the A and B components are added separately, rather than being premixed together, i.e., (A+B), followed by addition of either all component (C), or the active C component.

Thus a particularly preferred order of addition is: (1) mixed feed of butadiene'+hexane, (2) addition of an initial portion of component (C), (3) addition of component (A), (4) addition of component (B) and finally (5) addition of active portion of component (C). The A and B components may also be added simultaneously to the mixed feed, in the correct molar proportions.

, Using the five-step order of addition indicated 'above, the premix (A-I-B) is made in situ, in the polymeriza- 3,433,778 3 4 accompanying table. The reactions were performed in 21 Example 11' clean, dry nitrogen-purged bottle of 250 ml. capacity, the The Procedure of Example 8 was followed and the bottle fitted with a screw.oap cpntaining 1191c and a butadiene polymerized with the following catalyst charge neoprene gasket to enable ingredients and solutions to be butyl lithium 058 mM nickel dips (0 53 mM added by means of a hypodermic syringe. After filling Z with 160 cc. hexane followed by 40 cc. butadiene and m chlonde (0'53 and butyl hthlum (0'53 the catalyst components, each bottle was placed in a At 0 C 10% yield of polymer was obtained with constant temperature bath fitted Wlth an 'agltator mecha an inherent viscosity of 0.5 and micro structure correnism, ten The POlYmers were Worked by sponding to 92.1% cis 1:4, 5.2% trans 1:4. 2.7% vinyl pouring the reaction solution into ethanol when the 10 I product precipitated. The polybutadienes were carefully What i claimed dried under nitrogen, weighed and an LR. analysls of the 1. A process for the preparation of polybutadiene in cis 1,4 content made. which at least 80% of the monomer units are present in Example Order of LiBu Ooncentra- LiBu/SnCli Ni Dips/SnClt Polymerization Yield polybuta- Cis content of No. addition tion mols in 40 cc. ratio r io temperature C.) diene gas polymer butadiene 0. 42 1 1 55 is 90.1 0. 42 1 1 40 96.2 0. 42 1 0.5 55 14 95.0 0.42 0 9 0 2 55 3 94.8 0. 42 1 1 55 0 5 9e 0. 42 1 1 55 0 7 93. 0 0. 42 1 1 1 55 10 95.8

1 LiBu/GaOla. 2 Ni dipslGaGla.

The following Examples 8-11 show the working of the cis 1,4 addition structure, wherein butadiene is polymerinvention when component (C) is added in two portions: ized in the presence of a catalyst system obtained by rin in th n l ted r m the Example 8 b g g toge er (A) a compou (1 se ec f o gruop comprising cobalt or nickel carboxylic acid salts y lithium 0% Wt./vol.) was diluted to 0.5% and organic complexes in which the metal atom is other with pre-purified heXa under y Oxygen-free nitrogenthan zerovalent, (B) a compound selected from the group Nickel P PY salicylate Ni p Was used as a comprising the chlorides of gallium and tin and (C) an 2% solution in pre-purified hexane and SnCl as a 2% organo-metallic compound of lithium selected from the solution in benzene. group comprising lithium alkyls, lithium aryls and lithium The polymerization was conducted in a 10 oz. hydroaralkyls, the lithium component (C) only being contacted gen peroxide bottle which was first dried at 170 C. for with the other components of the catalyst system when 12 hours and on cooling was flushed with nitrogen (prein the presence of butadiene. purified for /2 hour). The bottle was fitted with a vacuum- A process for the preparation of polybutadiene in dried rubber gasket and a screw aluminum cap. 25 gm. of at f 80% of the mohofnel' 'f Present 111 dry gaseous butadiene was condensed into the bottle, now 015 1,4 addltloh Structure, Wherem hutadlene 1S P y o f now d b 90 of 40 ized in the presence of a catalyst system obtained by acme butyl hthlum (053 y h order- Fwe organo-metallic compound of lithium selected from the mlmltes Was allowed for the nlckel P 511014 and group comprising lithium alkyls, lithium aryls and lithium butadiene to react. The bottle was placed in a water aralkyls, i which the molar ratio f component (A) to bath in a wire cage at C. for 8 hours. At the en f component (B) lies within the range 0.01-1.0:1 and the this time, the bottle was removed and sufiicient antimolar ratio of component (C) to component (B) lies oxidant (Stavox) was added to provide approximately within the range 0.5-2.5:1, the lithium component (C) 1-2% b i ht of i-o ida t n th olymer, The only being contacted with the other components of the cement was then coagulated with methanol and the catalyst System When In t p sence of butadiene.

precipitated polymer was dried under vacuum at 40 C. h 'h tli t sgg tleflffepal'atioll 0f lz y t i 1 o he t cos-t 1.2 was w 10 a eats a o e monomer um s are presen in 50% yleld of p0 ymer f m ten vls W 018 1,4 addltion structure, wherein butadiene is polymertained.

The product was examined by infraqed analysis by ized at a temperature in the range of from 0 C. to 100 C., in the presence of a catal st system obtained b brin the method P HamPten (Anal' Chem 1949 ing together (A) a compou hd selected 'from th grou p The C15 1,4 content of the Polymer was 953% comprising cobalt or nickel carboxylic acid salts and 2 trans 114 and 23% W organic complexes in which the metal atom is other than Example 9 zerovalent, (1B) 11 colmpotfmd 11selecteddfrom tli1e( group comprisingt e c ori es 0 a ium an tin an C an Procedure P 'f 8 and the organo-metallic compound o f lithium selected from the butadiene polymerized with the tollowing catalyst charge: group comprising lithium alkyls, lithium aryls and lithium butyl llthlllm Illekd f l aralkyls, in which the molar ratio of component (A) to Staflnic chloride -L hutyl 1131111111 component (B) lies within the range 0.01-1.0:1 and the The polymerization was car ied out at 0. molar ratio of component (C) to component (B) lies Polymer was obtained in 40% yield having an inherent within the range from 0.5-2.5:1, the lithium component viscosity of 1.0. (C) only being contacted with the other components of Example 10 the catalyst system when in the presence of butadiene.

4. A process according to claim 1 in which the molar The procedure of Example 8 was followed and the ratio of component (A) to component (B) lies within the Polymel'lzatlon calmed out at 25 range from 0.05-0.25 :1 and the molar ratio of component Polymer was obtained in 15% yield with an inherent (C) t component (B) li ithi h range fr viscosity of 2.0. 15:1.

5. A process for the preparation of polybutadiene in which at least 80% of the monomer units are present in cis 1,4 addition structure, wherein butadiene is polymerized in the presence of a catalyst system obtained by bringing together (A) a compound selected from the group comprising nickel di-isopropyl salicylate, nickel acetylacetonate, nickel octoate, nickel naphthenate, nickel benzoate, nickel acetoacetate, cobalt acetylacetonate, cobalt octoate, and cobalt di-isopropyl salicylate, (B) a compound selected from the group comprising tin tetrachloride and gallium trichloride and (C) an organo-metallic compound of lithium selected from the group comprising n-butyl lithium, ethyl lithium, phenyl lithium, octyl lithium, sec-butyl lithium and iso-butyl lithium, in which the molar ratio of component (A) to component (B) lies within the range 0.011.0:1 and the molar ratio of component (C) to component (B) lies within the range 0.5-2.5 :1, the lithium component (C) only being contacted with the other components of the catalyst system when in the presence of butadiene.

6. A process for the preparation of polybutadiene in which at least 80% of the monomer units are present in cis 1,4 addition structure, wherein butadiene is polymerized in the presence of a catalyst system obtained by bringing together (A) a compound selected from the group comprising nickel di-isopropyl salicylate, nickel acetylacetonate, nickel octoate, nickel naphthenate, nickel benzoate, nickel acetoacetate, cobalt acetylacetonate, cobalt octoate, and cobalt di-isopropyl salicylate, (B) a compound selected from the group comprising tin tetrachloride and gallium trichloride and (C) an organo-metallic compound of lithium selected from the group comprising n-butyl lithium, ethyl lithium, phenyl lithium, octyl lithium, sec-butyl lithium and iso-butyl lithium, in which the molar ratio of component (A) to component (B) lies within the range 0.011.0:1 and the molar ratio of component (C) to component (B) lies within the range 0.52.5:1, the lithium component (C) only being contacted with the other components of the catalyst system when in the presence of butadiene, and the polymerization being carried out in a substantially dry hydrocarbon solvent.

7. A process according to claim 6 in which the hydrocarbon solvent is selected from the group comprising hexane and benzene.

8. A process according to claim 6 in which traces of water, within the range 1-20 parts per million in the solvent, are added to the solvent.

9. A process according to claim 1 in which the polymerization is carried out at a temperature within the range from 40-60 C.

10. A process for the preparation of ploybutadiene in which at least 80% of the monomer units are present in cis, 1,4 addition structure, wherein butadiene is polymerized in the presence of a catalyst system obtained by bringing together (A) a compound selected from the group comprising nickel di-isopropyl salicylate, nickel acetylacetonate, nickel octoate, nickel naphthenate, nickel benzoate, cobalt acetylacetonate, cobalt octoate and cobalt di-isopropylsalicylate, (B) a compound selected from the group comprising tin tetrachloride and gallium trichloride and (C) an organo-metallic compound of lithium selected from the group comprising nbutyl lithium, ethyl lithium, phenyl lithium, octyl lithium, sec-butyl lithium and isobutyl lithium, the lithium component (C) only being contacted with the other components of the catalyst system when in the presence of butadiene, the butadiene first being contacted with a proportion of component (C) and thereafter with the components (A) and (B) and finally the balance of component (C) and the polymerization being carried out in the presence of a substantially dry hydrocarbon solvent.

11. A process according to claim 10 in which of the total amount of component (C) for purification is first contacted with the butadiene in the absence of the other catalyst components.

References Cited UNITED STATES PATENTS 3,328,376 6/1967 Bernemann, et al. 260-943 FOREIGN PATENTS 1,139,277 11/1962 Germany.

JOSEPH L. SCHOFER, Primary Examiner. R. A. GAITHER, Assistant Examiner.

U.S. Cl. X.R. 

